Electric switch



Patented Oct. 18, 1938 PA'TENT'OFFICE.

ELECTRIC swrron Sigwart Ruppel, Berlin, Germany; Frida Strauss, ne Ruppel, heir of said Sigwart Ruppel, de-

ceased Application November 28, 1934, Serial No. 755,192

I In Germany December 8, 1933 5Claims. (c1.2oo 1 4s) My invention relates to electric circuit breakers of the fluid or gas-blast type wherein the arc is traversed by a jet of fluid, and has for. its 7 v principal object" the provision of an improved' 5 circuit breaker of the aforesaid type wherein the arc can be interrupted by a fluid blast at moderate pressure. J

In gas blast circuit breakers involving a flow of gas under pressure, the breakercontacts are 10 usually arranged to separate at the point of maximum blast effect. engagement of the contact elements is, 1ocatd at the narrowest'cross section of the fluid path, such as the neck of a nozzle, through which the gas under pressure flows, the movablecontact being actuated in a direction axial of'the nozzle in the circuit opening operation. The nterruption of the arc-occurs, therefore, between the neck of the nozzle and the tip of the movable l contact when the movable contact is withdrawn from the neck of the nozzle, so as to lengthen the arc, and is within a range where the gas flow may be comparatively weak. With this arrangement a comparatively high gas. pressure 35 is required in order to obtain reliable current interruption. s

In accordance with my invention 'a compressed gas or gas blast circuit breaker is pro-,

vided with a nozzle consisting entirely of insulat- U ing material. The stationary contact is mounted as an opposite pole in a widenedor exhaust part of the aforesaid nozzle beyond the neck,

and the movable contact is actuatedduring the opening movement through the neck and into 35 the space beyond the neck.

With this arrangement the stationary contact is disposed as a counter-pole within the con-' centrated jet of compressed gas and is emciently cooled thereby. Also, the higher pressure of 40 the gas at that point effects rapid evacuation of the conducting gases therefrom during the expansion. 7 The fresh gas following with considerable pressure maintains the region at thecounter-pole comparatively free of impure gas particles. As contrasted with prior ,types of. gas 'yblast breakers, the narrow neck. of the nozzle need not be considered as a possible base for the arc since the nozzle consists entirely of suitable insulating material and since no parts-of the stationary contact are" located within the neck of the nozzle.

It is preferable to design the stationary contact as a counter-pole, both as regards position and shape, in such a manner that no eddies 55 will occur in the vicinity thereof and so that In general, the point of.

. merit.

the base of the arc can travel in accordance with the blast effect. To this end contacts in the shape of pipes and rods are suitable, the axis of which is in the direction of the gas blast. 'However, supporting walls and ribs, having the wellknown tear drop cross section, disposed at right angles to the direction of the blast can be used as counter-poles. The effect is particularly favorable if a widened space is behind the counter-electrodes in the direction of the blast 10 so that removal of the ionized gas particles from the counter-electrodes is insured.

Owing to the fact that the stationary contact serving as counter electrode is arranged in the widened portion of the nozzle, the position of the arc is determined in a definite manner or in ..or of any other shape; the counter electrodes 7 have to be shaped in accordance with the shape of the switch chamber.

Any suitable gases may be used for blowing, i. e. gases with additions, steam or the like. The gases may be supplied from separate places of production, from reservoirs, bottles or the like; they may be driven into the switch chambers whi st the same is moving or they may be produced by the effect of the arc or of the current.

Some of the possible embodiments of the inventlon willbe hereinafter described with ref- 0 erence to the accompanying drawing in which :I- I Fig. 1 shows in vertical section partly in elevation a'switch according to the invention.

Fig. 2 shows 'a' modified contact arrangement. Fig. 3 shows-a thirdform of the contact arrangement. V l

Fig. 4 is a-iverti'cal section through Fig. 3. Fig. 5 is a horizontal section throughFlg. 4.v Fig. f5 shows a further form'of contact arrangefl'he movable contact I shown in Fig. 1 is tubular,ZpdeSignates thestationary contact, '3 the insulatingswitch casing, 4, 5 the terminals, Bthe adm ssion of compressedair or gas, Tthe actuating'swit'ch piston, 8 the inuflling device or damper.

The insulating casing 3 is nozzle-shaped at the switch point. The movable contact extends through the narrowest point 3' of the nozzle. The stationary contact 2, carried by ribs 9, is in the widened or exhaust portion of the nozzle so that it acts as counter. electrode and the base point of the arc in the widened portion of the nozzle can settle on this counter electrode. The ribs carrying the counter electrode serve at the same time as terminal conductor.

The current in the switched in state of terminal 5 flows through the tubular contact I, the counter electrode 2 and the ribs 9 to the terminal 4. The counter electrode 2 is preferably an elongated body of oval longitudinal section so that its outer surface extends essentially in streamline shape, and the formation of eddies is avoided. The contact is established in that the top end of the tubular contact I, which transmits the current to the counter electrode 2 is pressed through the interior of the tube to the contacts.

The arrangement may be such that in the swiciied in state no gas or only very little gas flows out from the space H.

The switching-out is eifected when the air admission 6 is connected with a container of com-,

pressed air. The compressed air flows then into the space above the piston i so that the movable contact descends through the neck 3'. The compressed air blows strongly through the neck 3' on to the contacts so that by the blowing efict and by the cooling effect of the flowing pressure gas the arc is extinguished by moderate gas pressure in or at the restricted portion 3'. The switching in is effected by admitting compressed air into the space below the piston. In this arrangement not only the switch chamber but also the nozzle and the damper may be made of insulating material. The whole switch may also be easily encased and insulated.

In Fig. 2 the stationary contact consists of a tube H2. The construction shown in Fig. 2 differs from that shown in Fig. 1 further in that there are no holes in the movable contact I 'so that, in open circuit state, the gas admission takes place directly from the switch chamber ll through the narrowest point of the nozzle. The tube I2 may evidently be telescoped over instead of in the movable contact I, this modification altering not the character of the construction.

. For reducing the friction of the gas the ribs 9 may be of drop-shaped cross section shaped according to the stream lines.

In the form of construction illustrated in Figs.

3 to 5 the ribs 9, preferably of drop-shaped cross section, form the stationary contact. The top end of the movable contact I3 is in the form of a pin with sphericalpoint. This point, especially its upper portion, is preferably made of material not easily evaporative, for instance tungsten. The counter electrodes or portions of the same may also be of tungsten.

InFig. 6 the counter electrode consists of two plate-shaped bodies HL which transmit the contact pressure, by separate springs and by other suitable means, upon the switch blade. The nozzle of the casing 3 and the space H may be adapted to the shape of the switch blade and of the counter electrodes I4. The nozzle will then be preferably of oval or rectangular shape, its

dimensions corresponding to the shape of the switch blade.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

I claim:-

1. A gas blast circuit breaker comprising a nozzleconsisting of insulating material, a stationary contact mounted in the exhaust part and beyond the neck and along the longitudinal axis of the nozzle, a coacting movable contact reciprocally operable through said neck and into the space at the opposite side thereof, said neck being restricted with respect to said movable contact, and means for directing gas under pressure through said nozzle in a direction counter to circuit opening movement of said movable contact to extinguish the arc at said neck.

- 2. A gas blast circuit breaker comprising a nozzle consisting of insulating material, a stationary contact disposed in a widened diverging part beyond the neck and along the longitudinal axis'of said nozzle, said contact presenting an inappreciable resistance to gas exhausting from said neck, a coacting movable rod contact reciprocally operable through said neck and into the space at the opposite side thereof, said movable contact having a comparatively close fit within said neck, and means for directing a gas under pressure upon opening of the circuit through said nozzle towards said stationary contact for traversing the arc at said neck, said gas freely exhausting through said diverging part without restriction to a low pressure area.

3. An electric gas-blast switch provided with a nozzle of insulating material comprising a constriction and a gradually widening portion ade joining the constriction on one side, a chamber for gas under pressure adjoining the nozzle on the other side, a fixed contact on the side of the constriction remote from the chamber, said i fixed contact being located along the longitudinal the chamber.

4. A gas-blast circuit breaker comprising a nozzle of insulating material having a constriction and a gradually widening portion adjoining the constriction on one side, a, source of gas pressure adjoining the nozzle at the other side for causing a. gas blast through said nozzle, a fixed contact mounted within said widened portion in an unobstructing position and spaced from said constriction, metallic rib members extending transversely of said 'nozzle for supporting said fixed contact, said rib members'and fixed contact being generally of stream-line configuration so as to have minimum resistance to gas fiow through said nozzle, and a movable rod contact reciprocally operable through said constriction to engage said fixed contact, circuit-opening movement of said rod contact being in a direction velocity gas blast within said constriction.

5. A gas blast circuit breaker comprising an insulating nozzle, an electrode connected to one terminal of the circuit arranged to be disposed at the exhaust part and beyond the neck of said 10 nozzle, a coacting movable electrode connected to the other terminal of the circuit reciprocally operable through said neck and into the space at the opposite side thereof to engage said firstnamed electrode, said neck being restricted with respect to said movable electrode, and means for directing gas under pressure through said nozzle in a direction counter to the circuit opening movement of said movable electrode to extin-,

guish the arc substantially at said neck.

SIGWART RUPPEL. 

